Is there a way to prevent EF from inserting into a SQL Server computed column?

user_13006563 0
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I don't want EF to ignore the column on the class when retrieving records from the database as I need to be able to compare the computed column, but I don't want EF to try to insert values into this column as that will throw a SQL Exception because computed columns cannot be modified.

entity-framework sql-server c#
3 Answers

You can use DatabaseGenerated attribute:

using System.ComponentModel.DataAnnotations.Schema;
....

[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
public int ComputedColumn { get; set; }
user_56496260

DatabaseGeneratedOption.Identity

This specifies that the value of the property will be generated by the database on the INSERT statement. This Identity property cannot be updated. 

[DatabaseGenerated(DatabaseGeneratedOption.Identity)] 
public int Id { get; set; }

DatabaseGeneratedOption.Compute Specifies that the value of the property will be generated by the underlying database on insert and then, on each subsequent update. Useful for LastAccessTime and things like that

user_34201390

If you are using the fluent API in OnModelCreating then you can use

entity.Property(e => e.ComputedColumn)
      .ValueGeneratedOnAddOrUpdate();

There is also a ValueGeneratedOnAdd and ValueGeneratedOnUpdate if the value is only computed on insert or update respectively.

user_8012050
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